The objective of this research is to gain an understanding of relapse to tobacco dependence, and to develop treatments based on this understanding. In the current funding period, we completed a placebo controlled, double blind study of active vs. placebo nicotine gum crossed with two levels of behavioral treatment, intensive vs. low contact. We report excellent preliminary abstinence rates in the nicotine gum low contact condition (56% at 6 months, 46% at one year). These rates are especially impressive since the treatment is inexpensive to administer and could be adapted to many health settings. The results replicate and improve upon those we obtained in earlier studies. In a series of studies, possible determinants of weight gain after quitting smoking were investigated. Preliminary conclusions are that high pretreatment cigarette intake, a past history of weight problems, and a tendency towards periodic loss of control over eating predispose subjects to weight gain after quitting. This gain may be caused by increased caloric intake, especially of sweets and foods high in carbohydrates. These findings may link the problem of weight gain after quitting smoking to the more general problem of weight regulation. In the current funding period, the focus of the research is shifted from the general smoking treatment population to two special subgroups: smokers at risk for post-quitting weight gain, and chronic smoking treatment failures. Two experiments are proposed, both of which draw from work during the current funding period. In Experiment 1, smokers at high risk for weight gain following quitting smoking are randomly assigned to an innovative weight management program, a nonspecific treatment control, or to no weight treatment control. Measures are taken at baseline, and at weeks 4, 8, 26, and 52. They include self-report of smoking, confirmatory biochemical measures, and reports of significant others. Weight gain, skinfold thickness, dietary intake, and activity levels are also assessed. In Experiment 2, chronic smoking treatment failures are assigned to brief cognitive behavioral psychotherapy plus 2 or 4 mg. nicotine gum or to 2 or 4 mg. nicotine gum in a low contact group treatment. Assessments are held at weeks 6, 12, 26, and 52. Treatment outcome measures parallel those for Experiment 1. Self-report of smoking, biochemical measures, significant other verification, and measures of thinking and mood are collected.